Blowout Preventer with Pipe Ram Packer Assemblies with Support Tab

ABSTRACT

A pipe ram blowout preventer may be used for sealing about an object positioned in a vertical bore extending through the blowout preventer. The blowout preventer includes a pipe ram assembly movable towards the tubular, the pipe ram assembly including a packer assembly comprising an elastomeric body for sealing against the object. The packer assembly includes an upper plate position above the elastomeric body which includes a tab extending from the upper plate. The tab resists extrusion of the elastomeric body in high temperature environments by containing the elastomeric material and forming a metal-to-metal seal about the object positioned in the blowout preventer vertical bore.

BACKGROUND

This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the presently described embodiments. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present embodiments. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.

Blowout preventers are used extensively throughout the oil and gas industry. Typical blowout preventers are used as a large specialized valve or similar mechanical device that seal, control, and monitor oil and gas wells. The two categories of blowout preventers that are most prevalent are ram blowout preventers and annular blowout preventers. Blowout preventer stacks frequently utilize both types, typically with at least one annular blowout preventer stacked above several ram blowout preventers. The ram units in ram blowout preventers allow for shearing drill pipe in the case of shear rams, and sealing off around drill pipe in the case of pipe rams. Typically, a blowout preventer stack may be secured to a wellhead and may provide a safe means for sealing the well in the event of a system failure.

A typical blowout preventer includes a main body or housing with a vertical bore. Ram bonnet assemblies may be bolted to opposing sides of the main body using a number of high tensile fasteners, such as bolts or studs. These fasteners are required to hold the bonnet in position to enable the sealing arrangements to work effectively. Typically an elastomeric sealing element is used between the ram bonnet and the main body. There are several configurations, but essentially they are all directed to preventing a leakage bypass between the mating faces of the ram bonnet and the main body. Each bonnet assembly includes a piston which is laterally movable within a ram cavity of the bonnet assembly by pressurized hydraulic fluid acting on one side of the piston. The opposite side of each piston has a connecting rod attached thereto which in turn has a ram mounted thereon. The rams can be shear rams for shearing an object within the bore of a blowout preventer. Alternatively, the rams can be pipe rams for sealing off around an object within the bore of a blowout preventer, thereby sealing the annular space between the object and the blowout preventer bore.

These rams are designed to move laterally toward the vertical bore of the blowout preventer to shear or seal off on any object located therein. For instance, opposing pipe rams utilize seals that close in on and seal off on a tubular within the vertical bore of the blowout preventer, such as a section of drill pipe used during drilling operations. Each pipe ram typically has a semicircular opening in its front face to form a seal about half of the outer periphery of the object within the blowout preventer vertical bore. When the opposing pipe rams are closed, the opposing pipe rams engage each other and seal the entire periphery of the object, thereby closing off the annulus between the object and the blowout preventer bore.

Typical pipe ram assemblies can include a ram packer assembly including a packer body which is composed of an elastomeric or rubber material and is configured to seal off against the tubular within the vertical bore of the blowout preventer when the opposing rams are run into the closed position. The elastomeric or rubber material of the ram packer assembly body is positioned between upper and lower plates. The plates provide structure for the ram packer and facilitate insertion of the ram packer into a pipe ram assembly.

Ram packers are susceptible to mechanical wear, particularly at high temperature. For instance, at high temperatures, such as over 350° F., the elastomeric or rubber material of a ram packer can flow and extrude past the upper plate of the ram packer into the blowout preventer borehole. When this occurs, the sealing capability of the ram packer declines.

Accordingly, a pipe ram packer assembly that is suitable for sealing off on an object in a bore of a blowout preventer is desirable, particularly at high temperature. More particularly, a pipe ram packer assembly including an upper and/or lower plate that resists extrusion of the packer elastomeric body is desirable.

DESCRIPTION OF THE DRAWINGS

For a detailed description of the preferred embodiments of the present disclosure, reference will now be made to the accompanying drawings in which:

FIG. 1 shows a sectional view of a pipe ram blowout preventer in accordance with one or more embodiments;

FIG. 2 shows a perspective view of a ram assembly including a packer assembly in accordance with one or more embodiments;

FIG. 3 shows a perspective view of a packer assembly including an elastomeric body located therein in accordance with one or more embodiments;

FIG. 4 shows a perspective view of an upper plate of a packer assembly, the upper plate including a tab extending therefrom in accordance with one or more embodiments;

FIG. 5 shows a partial cross-sectional view of a tab extending from an upper plate of a packer assembly in accordance with one or more embodiments; and

FIG. 6 shows a partial cross-sectional view of a tab extending from an upper plate of a packer assembly in accordance with one or more embodiments.

DETAILED DESCRIPTION

The following discussion is directed to various embodiments of the present disclosure. The drawing figures are not necessarily to scale. Certain features of the embodiments may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in the interest of clarity and conciseness. Although one or more of these embodiments may be preferred, the embodiments disclosed should not be interpreted, or otherwise used, as limiting the scope of the disclosure, including the claims. It is to be fully recognized that the different teachings of the embodiments discussed below may be employed separately or in any suitable combination to produce desired results. In addition, one skilled in the art will understand that the following description has broad application, and the discussion of any embodiment is meant only to be exemplary of that embodiment, and not intended to intimate that the scope of the disclosure, including the claims, is limited to that embodiment.

Certain terms are used throughout the following description and claims to refer to particular features or components. As one skilled in the art will appreciate, different persons may refer to the same feature or component by different names. This document does not intend to distinguish between components or features that differ in name but are the same structure or function. The drawing figures are not necessarily to scale. Certain features and components herein may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in interest of clarity and conciseness.

In the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . .” Also, the term “couple” or “couples” is intended to mean either an indirect or direct connection. In addition, the terms “axial” and “axially” generally mean along or parallel to a central axis (e.g., central axis of a body or a port), while the terms “radial” and “radially” generally mean perpendicular to the central axis. For instance, an axial distance refers to a distance measured along or parallel to the central axis, and a radial distance means a distance measured perpendicular to the central axis. The use of “top,” “bottom,” “above,” “below,” and variations of these terms is made for convenience, but does not require any particular orientation of the components.

Reference throughout this specification to “one embodiment,” “an embodiment,” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present disclosure. Thus, appearances of the phrases “in one embodiment,” “in an embodiment,” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment.

Referring now to FIG. 1, a sectional view of a pipe ram blowout preventer 10 in accordance with one or more embodiments is shown. The blowout preventer 10 includes a housing 12, such as a hollow body, with a vertical bore 14 that enables passage of fluid or an object, such as a tubular member, through the blowout preventer 10. The housing 12 further includes one or more cavities, such as ram cavities 16 opposed from each other with respect to the vertical bore 14, with a pipe ram assembly 18 movably positioned within each cavity 16. The blowout preventer 10 may be coupled to other equipment that facilitates natural resource production. For instance, production equipment or other components may be attached to the top of the blowout preventer 10 using a connection 20 (which may be facilitated in the form of fasteners), and the blowout preventer 10 may be attached to a wellhead or spool using the flange 22 and additional fasteners.

One or more bonnet assemblies 24 are secured to the housing 12 and include various components that facilitate control of the ram assemblies 18 positioned in the blowout preventer 10. The bonnet assemblies 24 are coupled to the housing 12 by using one or more fasteners 26 to secure the bonnets 28 of the bonnet assemblies 24 to the housing 12. The ram assemblies 18 are then actuated and moved through the cavities 16, into and out of the bore 14, by operating and moving a piston 30 and a rod 32 coupled thereto within a housing 34 of the bonnet assemblies 24.

In operation, a force (e.g., from hydraulic pressure) may be applied to the pistons 30 to drive the rods 32, which in turn drives the rams 18 coupled thereto into the bore 14 of the blowout preventer 10. The ram assemblies 18 cooperate with one another when driven together to seal the bore 14 and inhibit flow through the blowout preventer 10.

In this embodiment, a hydraulic actuator is shown, though any type of actuator (e.g., pneumatic, electrical, mechanical) may be used in accordance with the present disclosure. As such, this embodiment may include a piston 30 and a rod 32 connecting the piston 30 to ram assembly 18. Further, pressurized fluid may be introduced and fluidly communicated on opposite sides of the piston 30 thereby enabling the piston 30 to move the ram assembly 18 in response to fluid pressure.

Turning now to FIG. 2, a ram assembly 200 including a packer assembly 202 in accordance with one or more embodiments is shown. Ram assembly 200 is similar to ram assembly 18 illustrated in FIG. 1. Ram assembly 200 includes a ram body 204, top seal 206, and packer assembly 202. Ram body 204 has generally rounded sides 208 that fit in laterally disposed ram cavities of a blowout preventer, such as ram cavities 16 illustrated in FIG. 1.

Ram body 204 includes an upper body 210 and a lower body 212 connected by front face 214 and defining a packer assembly cavity therebetween. In the illustrated embodiment, packer assembly 202 is inserted within the packer assembly cavity. Formed within front face 214 of upper body 210 is ram bore profile 216. Ram bore profile 216 is substantially semi-circularly shaped and extends vertically through upper body 210 and lower body 212 to packer assembly 202.

Turning now to FIG. 3, a packer assembly 300 in accordance with one or more embodiments is shown. Packer assembly 300 is similar to packer assembly 202 illustrated in FIG. 2. Packer assembly 300 includes an upper plate 302 and a lower plate 304. Upper plate 302 includes a tab 312 extending downwardly from upper plate 302. Tab 312 is configured to resist extrusion of packer assembly body 306 into the blowout preventer bore and to form a metal-to-metal seal with the object in the bore. Packer assembly body 306 is molded in a semi-elliptical shape and positioned between upper plate 302 and lower plate 304. Body 306 can be molded in any desired shape, such as semi-elliptical, elliptical, circular, etc.

Body 306 is fastened to upper plate 302 via fasteners 308, such as screws or bolts. Body 306 is likewise coupled to lower plate 304 via fasteners, which are not shown in this illustration. In the illustrated embodiment, four fasteners 308 are shown. However, any number of fasteners may be used to secure body 306 to upper plate 302 and lower plate 304. A packer bore profile 310 is formed through upper plate 302, lower plate 304, and body 306. Body 306 is configured to be coupled to a ram assembly, such as ram assembly 200 illustrated in FIG. 2, by way of fasteners 314. One fastener 314 is positioned on each side of body 306 and configured to couple body 306 to a ram assembly. However, any number of fasteners 314 may be used.

Packer assembly body 306 is constructed of an elastomeric material, such as any synthetic or natural rubber, or combination thereof. Body 306 is configured to seal about an object located within a vertical bore of a blowout preventer when packer assembly 300 is moved to a closed position. In particular, body 306 is configured to seal about 180° of the object to be sealed upon. A corresponding packer assembly body in a corresponding packer assembly closes on the object from the opposing side and seals about the other 180° of the object. Exemplary objects to be sealed upon include a drill pipe joint, a casing joint, and a tool joint. In this way, packer assembly 300, together with a corresponding and opposing packer assembly run from an opposing side, provides for a fluid seal in the annular region between an object in a blowout preventer borehole and the blowout preventer housing. Packer assembly body 306 may include one or more inserts within body 306 to enhance the sealing ability of elastomer 306.

Turning now to FIG. 4, packer assembly 400 in accordance with one or more embodiments is shown, with the elastomer and fasteners removed, thereby revealing upper plate 402 and tab 404. Tab 404 is shown extending downwardly from upper plate 402. In the illustrated embodiment, tab 404 is shown extending from upper plate 402 in the bore profile 406 of packer assembly 400. That is, tab 404 does not extend along the generally straight edges 408 of upper plate 402, but is only located along the semi-circular portion 410 of upper plate 402. However, in other embodiments tab 404 can extend from upper plate 402 along the generally straight edges 408 of upper plate 402 only, or in addition to extending from the semi-circular portion 410 of upper plate 402. In addition, tab 404 can be integral with upper plate 402, i.e., upper plate 402 and tab 404 are constructed from a single piece of material. In alternative embodiments, tab 404 can be constructed of a different material than upper plate 402.

Tab 402 is configured to resist packer assembly body elastomer flow and extrusion, particularly at high temperatures, such as temperatures above about 350° F. (approximately 177° C.), particularly at temperatures above about 400° F. (approximately 205° C.). As discussed above, it is common for elastomeric packer bodies to flow and extrude into the blowout preventer bore at such high temperatures. When the elastomeric material flows into the blowout preventer bore, the sealing efficiency of the packer assembly diminishes. Tab 402 essentially functions as a barrier for the elastomeric body, preventing the elastomer material from flowing into the blowout preventer bore when the elastomer material flows. Tab 402 contains the elastomer material while still allowing the packer assembly to seal about an object in a blowout preventer bore during closing operations. In addition, tab 402 is configured to form a metal-to-metal seal with the object positioned within the blowout preventer bore when packer assembly 400, together with an associated ram assembly, is closed on an object in a blowout preventer bore during closing operations.

Tab 402 can be incorporated into the packer assemblies of newly manufactured ram assemblies. Alternatively, tab 402 can be retrofitted to an existing ram assembly. In this way, older pipe ram assemblies can be retrofitted to extend the life of the ram assemblies and enable existing assemblies for use in higher temperature environments.

Turning now to FIG. 5, a partial cross-sectional view of ram assembly 500 in accordance with one or more embodiments is shown. Ram assembly 500 is similar to ram assembly 200 illustrated in FIG. 2. Ram assembly 500 includes an upper plate 502, which comprises a tab 504, and a packer body 506. Packer body 506 comprises an elastomer material configured to seal about the wall of an object 508 positioned in a blowout preventer bore. As illustrated, ram assembly 500 is run in to a closed position, i.e., is in a position in which tab 504 and body 506 are in contact with object 508. Tab 504 forms a metal-to-metal seal with the wall of object 508, thereby preventing fluid flow vertically across an annular region formed between object 508 and the blowout preventer bore. Likewise, body 506 forms a seal with object 508, also restricting flow. As discussed above, tab 504 will prevent extrusion of body 506 into the bore of the blowout preventer, thereby preserving the sealing capability of body 506. The lower portion of tab 504 extends laterally toward the object 508 as a result of elastomer 506 pushing against tab 504. Tab 504 can return to its original position (i.e., parallel to the bore of the blowout preventer) when it seals against object 508.

Upper plate 502 includes a height H_(P) and tab 504 includes a height H_(T). Tab 504 extends downwardly from upper plate 502 and height H_(T) is greater than height H_(P). The difference between heights H_(T) and H_(P) is the length of the tab 504 extension beyond the bottom surface of upper plate 502. Heights H_(T) and H_(P) and the length of the extension beyond the bottom surface of upper plate 502 can be optimized depending on the size of packer assembly 500, the size of object 508 to be sealed upon, or any other design considerations.

Turning now to FIG. 6, a partial cross-sectional view of ram assembly 600 in accordance with one or more embodiments is shown. Ram assembly 500 is similar to ram assembly 200 illustrated in FIG. 2. Ram assembly 600 includes an upper plate 602, which comprises a tab 604, and a packer body 606. Packer body 606 comprises an elastomer material configured to seal about the wall of an object 608 positioned in a blowout preventer bore. As illustrated, ram assembly 600 is run in to a closed position, i.e., is in a position in which tab 604 and body 606 are in contact with object 608. Tab 604 forms a metal-to-metal seal with the wall of object 608, thereby preventing fluid flow vertically across an annular region formed between object 608 and the blowout preventer bore. Likewise, body 606 forms a seal with object 608, also restricting flow. As discussed above, tab 604 will prevent extrusion of body 606 into the bore of the blowout preventer, thereby preserving the sealing capability of body 606.

In addition to the embodiments described above, many examples of specific combinations are within the scope of the disclosure, some of which are detailed below:

Example 1

A packer assembly for a pipe ram blowout preventer configured to seal about an object located in a vertical bore of the blowout preventer, the packer assembly comprising:

-   -   an upper plate;     -   a lower plate;     -   a body positioned between the upper and lower plates, the body         comprising an elastomeric material and a surface configured to         engage the object; and     -   a tab extending from one of the upper and lower plates, wherein         the tab is configured to diminish extrusion of the elastomeric         material.

Example 2

The packer assembly of Example 1, wherein the tab extends from the upper plate.

Example 3

The packer assembly of Example 1, wherein the tab is configured to diminish extrusion of the elastomeric material during sealing operations at temperatures at or above about 350° F.

Example 4

The packer assembly of Example 1, wherein the body is semi-elliptical in shape.

Example 5

The packer assembly of Example 1, wherein the body is elliptical in shape.

Example 6

The packer assembly of Example 1, further comprising:

-   -   the upper plate further comprising a height H_(P); and     -   the tab comprising a height H_(T), wherein H_(T) is greater than         H_(P).

Example 7

The packer assembly of Example 1, wherein the upper plate and tab comprise different materials of construction.

Example 8

The packer assembly of Example 1, wherein the tab is further configured to form a metal-to-metal seal with the object.

Example 9

The packer assembly of Example 1, wherein the elastomeric material is synthetic or natural rubber

Example 10

The packer assembly of Example 1, wherein the object is one of a drill pipe joint, casing joint, or tool joint.

Example 11

A blowout preventer (“BOP”) assembly comprising:

-   -   a body comprising a vertical bore extending through the body and         a ram cavity intersecting the bore;     -   a hydraulically actuated pipe ram configured to seal about an         object located in the vertical bore, the pipe ram comprising a         packer assembly comprising:         -   a an upper plate;         -   a lower plate;         -   a body positioned between the upper and lower plates, the             body comprising an elastomeric material and a surface             configured to engage the object; and         -   a tab extending from one of the upper and lower plates,             wherein the tab is configured to diminish extrusion of the             elastomeric material.

Example 12

The BOP assembly of Example 11, where the tab is configured to diminish extrusion of the elastomeric material during sealing operations at temperatures at or above about 350° F.

Example 13

The BOP assembly of Example 11, wherein the body is semi-elliptical in shape.

Example 14

The BOP assembly of Example 11, wherein the body is elliptical in shape.

Example 15

The BOP assembly of Example 11, further comprising:

-   -   the upper plate further comprising a height H_(P); and     -   the tab comprising a height H_(T), wherein H_(T) is greater than         H_(P).

Example 16

The BOP assembly of Example 11, wherein the upper plate and tab comprise different materials of construction.

Example 17

The BOP assembly of Example 11, wherein the tab is further configured to form a metal-to-metal seal with the object.

Example 18

The BOP assembly of Example 11, wherein the elastomeric material is synthetic or natural rubber

Example 19

The BOP assembly of Example 11, wherein the object is one of a drill pipe joint, casing joint, or tool joint.

Example 20

The BOP assembly of Example 11, further comprising another an opposing hydraulically actuated pipe ram configured to seal about the object located in the vertical bore, the opposing pipe ram comprising a packer assembly comprising an tab extending from an upper plate.

While the aspects of the present disclosure may be susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and have been described in detail herein. But it should be understood that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the following appended claims. 

What is claimed is:
 1. A blowout preventer (“BOP”) assembly for sealing against an object, comprising: a body comprising a vertical bore extending through the body; pipe ram assemblies configured to seal about the object when located in the vertical bore, each pipe ram assembly comprising a packer assembly comprising: an upper plate; a lower plate; a body positioned between the upper and lower plates, the body comprising an elastomeric material and a surface configured to engage the object; and a tab extending from one of the upper and lower plates, wherein the tab is configured to diminish extrusion of the elastomeric material.
 2. The BOP assembly of claim 1, where the tab is configured to diminish extrusion of the elastomeric material during sealing operations at temperatures at or above about 350° F.
 3. The BOP assembly of claim 1, wherein the body is semi-elliptical in shape.
 4. The BOP assembly of claim 1, wherein the body is elliptical in shape.
 5. The BOP assembly of claim 1, further comprising: the upper plate further comprising a height H_(P); and the tab comprising a height H_(T), wherein H_(T) is greater than H_(P).
 6. The BOP assembly of claim 1, wherein the upper plate and tab comprise different materials of construction.
 7. The BOP assembly of claim 1, wherein the tab is further configured to form a metal-to-metal seal with the object.
 8. The BOP assembly of claim 1, wherein the elastomeric material comprises at least one of synthetic and natural rubber
 9. The BOP assembly of claim 1, wherein the object is one of a drill pipe joint, casing joint, or tool joint.
 10. The BOP assembly of claim 1, wherein the packer assemblies are each coupled to the ram assemblies via one or more fasteners.
 11. A packer assembly for a pipe ram blowout preventer configured to seal about an object located in a vertical bore of the blowout preventer, the packer assembly comprising: an upper plate; a lower plate; a body positioned between the upper and lower plates, the body comprising an elastomeric material and a surface configured to engage the object; and a tab extending from one of the upper and lower plates, wherein the tab is configured to diminish extrusion of the elastomeric material.
 12. The packer assembly of claim 11, wherein the tab extends from the upper plate.
 13. The packer assembly of claim 11, wherein the tab is configured to diminish extrusion of the elastomeric material during sealing operations at temperatures at or above about 350° F.
 14. The packer assembly of claim 11, wherein the body is semi-elliptical in shape.
 15. The packer assembly of claim 11, wherein the body is elliptical in shape.
 16. The packer assembly of claim 11, further comprising: the upper plate further comprising a height H_(P); and the tab comprising a height H_(T), wherein H_(T) is greater than H_(P).
 17. The packer assembly of claim 11, wherein the upper plate and tab comprise different materials of construction.
 18. The packer assembly of claim 11, wherein the tab is further configured to form a metal-to-metal seal with the object.
 19. The packer assembly of claim 11, wherein the elastomeric material comprises at least one of synthetic and natural rubber
 20. The packer assembly of claim 11, wherein the object is one of a drill pipe joint, casing joint, or tool joint. 